This article is devoted creation powerful plasmatron for various technological processes and carrying out of laboratory researches. Wide-ranging studies of the electric arc burning in a longitudinal argon stream in the metal cylindrical channel are with that end in view spent. The design procedure of generators of plasma streams - plasmatrons of direct current is developed by theory of similarity. Hardenings of metals, sedimentation of wearproof coverings are created plasmatron for carrying out of scientific researches and realisation of technological processes. Ihe description of one of developed plasmatron is resulted.